【摘 要】
:
A possible two steps mechanism was proposed for crystallization during polymerization of cyclic butylenes terephthalate(CBT)(Figure 1).In such scenario(Figure 2),the catalyst was introduced into the e
【机 构】
:
College of Petrochemical Technology,Lanzhou University of Technology,Lanzhou 730050
【出 处】
:
The 11th International Symposium on Polymer Physics(PP2014)(
论文部分内容阅读
A possible two steps mechanism was proposed for crystallization during polymerization of cyclic butylenes terephthalate(CBT)(Figure 1).In such scenario(Figure 2),the catalyst was introduced into the end of the ring opened cyclic molecules during ring opening polymerization(ROP)and the propagated chains crystallized preferentially.The living end with the metal atom of the catalyst was excluded from the crystal cells of pCBT due to their incompatible lattice parameters.The freshly ring-opened chain segments were always connected with a living catalyst end,making the living ends always dangling on the surfaces of the crystal nuclei,termed as living crystal seeds.These seeds played a role of intelligent transfer arms for the subsequent lamellae growth and finally evolved into living lamellar crystal which could initiate ROP continuously unless the reaction was quenched.In this case,it was difficult for the ring-opened chains to move freely or penetrate and fold into several lamellae which led to the lack of intercrystalline tie-molecules(Figure 3a)and resulted in the brittleness: the main disadvantage of pCBT than conventional PBT.All of this was demonstrated further by the crystallization kinetics(Figure 4)on the basis of Avrami equation.
其他文献
Using Brownian Dynamics simulation,we determine the chain orientation and stretching and their connection to stress overshoot in an entangled polymer melt undergoing startup shear at rates lower than
Block copolymer has been used to reduce the domain size of immiscible polymer blends in order to improve mechanical properties.This method,however,is not as effective,if a high percentage of the polym
The rheology of polymer blends has attracted great attention due to the scientific and industrial importance.These studies could be divided into the following categories:studies focused on the rheolog
Many materials,for instance water,glycerol,n-alcohol and polymer,have demonstrated physical property deviations from their bulk counterparts when they are in confinement.1,2 Such phenomena are very st
Polymer/carbon nanotube (CNT) nanocomposites have a wide range of applications.Recently,it is reported that when polymers are covalently linked with CNTs,the electronic properties of CNTs can be signi
Ultrafast differential scanning calorimeter (UFDSC) with scanning rate up to 1,000,000 K/s has already been used to study the kinetics of crystallization and phase transition of some polymers and liqu
Nafion is widely used as a proton exchange film in polymer electrolyte fuel cell (PEFC).Such excellent electrochemical and mechanical properties of Nafion are associated with the characteristic networ
A novel way of fabricating patterned porous surface with responsive functionalities has been demonstrated by applying thermo-responsive microgels assisted Breath Figure (BF) process.During the fast fo
Considering anisotropy and influence on shape memory characteristics caused by addition of carbon fiber,this work aims to describe the shape memory cycle and properties in three point bending deformat
Block copolymer is a special type of copolymer that comprises two or more chemically distinct polymer blocks covalently linked together.This special structure endows the block copolymer a variety of u